Prevalence of canine visceral leishmaniasis in the Xakriabá Indigenous Land, Minas Gerais state, southeast Brazil, 2011

Machado-Coelho, George Luiz

Prevalence of canine visceral leishmaniasis in the Xakriabá Indigenous Land, Minas Gerais state, southeast Brazil, 2011

Monday, 18 August 2014

Exhibit hall (Dena'ina Center)

Ana Maria S Rocha, BS , Federal University of Ouro Preto, Ouro Preto, Brazil

Erica M de Queiroz, PhD , Federal University of Ouro Preto, Ouro Preto, Brazil

Isabela D Teixeira , Federal University of Ouro Preto, Ouro Preto, Brazil

Naline S Jaques , Federal University of Ouro Preto, Ouro Preto, Brazil

Amanda F Vieira , Federal University of Ouro Preto, Ouro Preto, Brazil

Luciana S de Godoy , Federal University of Ouro Preto, Ouro Preto, Brazil

Eduardo C Ferreira, PhD , Fiocruz, Campo Grande, Brazil

Vivian W dos Reis, MS , Federal University of Ouro Preto, Ouro Preto, Brazil

Aline P Batista, BS , Federal University of Ouro Preto, Ouro Preto, Brazil

Edelberto S Dias, PhD , Fiocruz, Belo Horizonte, Brazil

Helida M de Andrade, PhD , Federal University of Minas Gerais, Belo Horizonte, Brazil

Jaime C da Silva, BS , SESAI, Governador Valadares, Brazil

Carolina C Marinho, PhD , Federal University of Ouro Preto, Ouro Preto, Brazil

Joao Carlos França-Silva, PhD , Federal University of Minas Gerais, Belo Horizonte, Brazil

George Luiz L Machado-Coelho, PhD , Federal University of Ouro Preto, Ouro Preto, Brazil

INTRODUCTION: Reports on the epidemiologic surveillance of leishmaniasis in Brazilian indigenous lands are scarce. Control measures recommended by the National Health Department are currently ineffective. One possible reason contributing to the perpetuation of the zoonosis cycle is the maintenance of canine reservoirs in endemic areas, either for mistakes in serologic diagnosis (false-negatives or indeterminate results) or delays in the systematic withdrawal of seropositive animals. The objectives were to detect the prevalence of leishmaniasis infection using serologic and molecular methods in dried blood samples in filter paper (DBS) and to identify the species of Leishmania sp. in DBS and tissue samples from infected native canines from 17 of 32 localities in the Xakriabá Indigenous Land.

METHODS: A canine population of 950 animals was examined. The immunoenzymatic assay (ELISA) was used as screening and the indirect immunofluorescence (IFI) was used as confirmatory (titles > 1:40 considered reagent) serologic test. One sample of 24 canines with positive serologic tests was selected for euthanasia and tissue sampling of: mesenteric lymph nodes, spleen, distal ear border and bone marrow. Parasite DNA was isolated from DBS and tissue samples by polymerase chain reaction (PCR-kDNA and PCR-FRLP) by using the primers A: 5’(C/G)(C/G)(G/C) CC(C/A) CTA T(T/A)T TAC ACC AAC CCC 3’ and B: 5’ GGG GAG GGG CGT TCT GCG AA 3’. Animals were grouped by serologic profiles: ELISA+/IFI+, ELISA+/IFI-, indeterminate ELISA/IFI+, indeterminate ELISA/IFI-, ELISA-. The proportion of positive diagnosis by the molecular method was compared between groups.

RESULTS: The prevalence of infection determined by PCR-kDNA was 13.3% (102/769), by ELISA 33.2% (314/947), and by IFI 13.5% (70/520). L. (L.) infantum was isolated from bone marrow samples.The percentage of positive diagnoses by molecular method varied significantly (p<0.001) according to serologic diagnostic criteria: ELISA+/IFI+ (n=37; 40.5%); ELISA+/IFI- (n=247; 16.6%), indeterminate ELISA/IFI+ (n=28; 57.1%), indeterminate ELISA/IFI- (n=97; 13.4%), ELISA- (n=356; 4.5%).

CONCLUSIONS: The molecular method evidenced a high frequency of failure of serologic methods at diagnosing canine infection, hindering the control measures in indigenous lands. In face of the vulnerability of these populations, the use of molecular methods is desirable for diagnosing infection in cases with serologic discordant results and to assure the effective control of this zoonosis. Grants: CNPq 481001/2010-7 and 4747771/2012-0.